Screw seals ND8 are made of PP and are supplied without or with fitted septa made of a variety of materials. They have a 8-425 thread, a 5.5 mm centre hole or are closed.

These septa are temperature-resistant from -60 °C to 200 °C and have better purity than septa made of natural rubber, butyl or red rubber. However, they have less effective resealability properties and are therefore more suitable for single-injection applications. Septa with a double-sided PTFE coating show a very low particle formation during penetration....